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WXIVERSlTY 


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UNITED   STATES  DEPARTMENT  OF  AGRICULTURE 

FARMERS' 
BULLETIN 

[ASHINGTON,  D.  C.  74.4  SEPTEMBER  21,  1916 

Contribution  from  the  Forest  Service,  H.  S.  Graves,  Forester. 


THE  PRESERVATIVE  TREATMENT  OF  FARM 

TIMBERS 

[Revised,  1915] 

By  GEORGE  M.  HUNT,  Chemist  in  Forest  Products,  Forest  Products  Laboratory^ 

CONTENTS. 


production 


Prolonging  the  life  of  ot 
timbers 

Conclusion... 


alonging  the  life  of  posts  without  the  use 

[f  preservatives 4 

iilonging  the  life  of  posts  by  means  of  pre- 

itives 7 


INTRODUCTION. 

•The  amount  of  wood  used  on  the  farms  of  the  country  and  exposed 
|  decay  is  very  great.  The  total  is  difficult  to  estimate,  but  it 
^doubtedly  amounts  to  several  billion  feet.  This  wood  is  used  in 

rious  forms,  such  as  fence  posts,  building  foundations,  windmill 
les,  shingles,  telephone  poles,  silos,  etc.     For  such  uses  durability 
[usually  the  chief  requisite. 
JSome  woods  resist  decay  more  than  others.     A  post  of  one  kind 

wood  may  last  10  years  or  more,  while  one  of  another  kind  may 
>t  only  two  years  under  the  same  conditions.  There  is  also  a 
it  difference  in  the  durability  of  wood  of  the  same  species  under 

Ferent  conditions.  In  a  very  wet  or  a  very  dry  situation  a  post 
11  last  longer  than  in  a  situation  where  the  ground  is  simply  damp. 

will  last  better  in  a  compact  clayey  soil  than  in  a  loose  sandy  soil, 
[warm,  moist  climate  is  more  favorable  to  decay  than  a  dry  ono, 
j  one  that  has  long,  cold  winters. 

Naturally  durable  woods  are  continually  growing  scarcer  and 
-jher  priced  in  most  localities,  and  less  durable  woods  must  be  used 

their  stead.     Many  of  these  woods   in   their   natural   condition 

>TE.~This  bulletin  is  of  value  to  all  who  are  interested  in  prolonging  the  life  of  building  timbers,  poles, 
I  jats,       Tcially  on  farms  at  a  distance  from  preservative  works. 
'  Tl861°—  Bull.  744—16 1 

477609 


FARMERS'  BULLETIN  744. 


will  last  only  two  or  throe  years  in  situations  favorable  to  decay. 
It  will  readily  be  seen,  therefore,  that  any  reasonably  cheap  method 
of  increasing  their  life  will  effect  a  material  saving  to  the  user. 

For  a  number  of  years  the  Forest  Service  has  been  conducting 
experiments  on  the  preservative  treatment  of  fence  posts,  poles,  and 
other  forms  of  timber  exposed  to  decay.  These  experiments  have 
been  made  in  cooperation  with  agricultural  experiment  stations, 
farmers,  and  various  companies,  and  also  upon  the  National  Forests. 
They  have  proved  conclusively  that  when  a  suitable  preservative 
treatment  is  given  the  resistance  of  wood  to  decay  can  be  very 

much  increased. 

DECAY. 

Decay  is  not  due  to  the  chemical  action  of  the  soil  or  to  the  fer- 
mentation of  the  sap,  but  is  the  result  of  the  action  of  certain  low 
forms  of  plant  life  called  fungi.  These  consist,  for  the  most  part, 
of  very  fine  thread-like  filaments,  collectively  called  mycelium, 
which  penetrate  the  wood  in  all  directions.  Certain  substances  in 
the  wood  constitute  the  food  of  the  fungi.  As  these  substances  are 
dissolved  the  structure  is  broken  down,  until  the  wood  reaches  tho 
condition  commonly  known  as  rotten. 

The  mycelium  usually  grows  out  to  the  surface  to  form  compact 
masses  called  fruiting  bodies.  Since  there  are  many  kinds  of  fungi, 
there  are  many  kinds  of  fruiting  bodies.  The  various  forms  of 
" toadstools/'  "punks,"  " brackets/'  or  "dog  ears/'  which  are  so 
frequently  found  growing  on  trees  and  deadwood,  are  examples  of 
these  (see  figs.  1  to  4).  Their  presence  generally  means  that  decay 
has  made  considerable  progress  in  the  wood.  The  function  of  all 
fruiting  bodies  is  to  produce  spores,  which  are  to  the  fungus  what 
seeds  are  to  higher  plants.  Millions  of  spores  may  be  produced  by  a 
single  fruiting  body,  and  they  are  so  small  that  they  are  able  to 
float  long  distances  in  the  air.  When  a  spore  drops  into  a  crack  in 
a  piece  of  wood  and  conditions  are  favorable,  it  germinates  and  the 
fungus  begins  its  destructive  action. 

Another  way  in  which  decay  spreads  is  by  the  mycelium  growing 
from  one  piece  of  wood  to  another.  When  a  piece  of  decaying  wood 
is  in  contact  with  a  sound  piece  the  latter  may  rapidly  become 
infected  in  this  way  and  be  ruined. 

The  four  requirements  for  the  growth  of  fungi  are  moisture,  air, 
a  favorable  temperature,  and  food. 

A  damp  condition  of  the  wood  is  probably  the  most  favorable 
to  decay.  Wood  can  be  either  so  wet  or  so  dry  that  the  fungi  can 
not  live  in  it.  When  submerged  in  water  it  has  been  known  to  last 
hundreds  of  years,  and  in  perfectly  dry  situations  it  will  often  last 
indefinitely.  Wood  in  contact  with  damp  ground  usually  contains 
the  right  amount  of  moisture  for  the  development  of  decay.  Also, 
where  timber  is  in  contact  with  wood  or  other  material,  water  fre- 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS. 


quently  collects  in  the  joints  and  keeps  the  wood  moist  for  long 
periods  of  time,  thus  favoring  decay  at  these  points.  Familiar 
examples  of  this  are  decay  in  the  tops  of  posts  in  board  fences  (see 
fig.  5),  in  the  joints  of  various  kinds  of  buildings  (see  fig.  6),  in  porch 
columns,  in  sills  resting  on  wood  or  stone  piers,  and  in  lumber  piles. 


FIG.  1.— Fruiting  body  of  fungus,  Lentinus  lecomtei. 

There  are  very  few  places  where  the  fungus  can  not  get  air  enough 
for  its  needs.  When  wood  is  buried  deep  in  the  ground,  especially  in 
compact  or  clayey  soil,  it  tends  to  become  saturated  with  moisture, 
so  that  decay  is  prevented ;  but  within  2  or  3  feet  of  the  surface  of  the 
ground  there  is  usually  enough  air  for  the  growth  of  the  fungus. 
Conditions  are  most  favorable,  of  course,  just  at  the  surface  of  the 
ground;  and  it  will  be  noted  that  the  point  of  greatest  decay  in  a 


FARMERS'  BULLETIN  744. 


fence  post  is  usually  near  the  ground  line.  Above  the  ground  line 
moisture  conditions  are  usually  unfavorable,  and  below  the  ground 
line  the  air  supply  is  less  favorable  for  the  development  of  decay. 
In  loose  or  sandy  soils,  however,  which  under  good  drainage  contain 

more  air  than  compact  soils, 
decay  may  extend  to  the  bot- 
tom of  the  post. 

Wood-destroying  fungi  can 
not  grow  at  very  high  or  very 
low  temperatures;  but  there 
are  few,  if  any,  climates  in 
which  the  temperature  during 
at  least  part  of  the  year  is  not 
favorable  to  their  growth. 

The  wood  itself  supplies 
the  fourth  requirement  of 
the  fungi,  which  is  food.  In 
order  to  prevent  decay,  it 
is  necessary  to  deprive  the 
fungus  of  one  or  more  of 
these  four  requirements.  It 
is  out  of  the  question  in 
ordinary  situations  to  de- 
prive it  of  air  and  warmth; 
and  though  moisture  can 
sometimes  be  eliminated  to 
a  certain  extent,  this  can 
not  be  done  when  the  wood 
is  exposed  to  the  weather. 
In  general,  therefore,  the 
most  effective  method  of 
preventing  decay  is  to  poison 
the  food  supply;  and  upon 
this  principle  is  based  the 
use  of  most  successful  wood 

FIG.  2. — Fruiting  body  of  fungus.  Poria  sp.  , . 

preservatives. 

PROLONGING  THE  LIFE  OF  POSTS  WITHOUT  THE  USE  OF  PRESERVA- 
TIVES. 

PEELING. 

Posts  which  are  to  be  set  without  preservative  treatment  should 
always  be  peeled.  The  presence  of  loose  bark  allows  moisture  to 
collect,  and  thus  makes  conditions  favorable  to  decay.  It  also  har- 
bors wood-boring  insects,  which,  by  boring  tunnels,  may  both  sen- 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS.  5 

ously  weaken   the  post   and  make  conditions  more  favorable  for 
rapid  decay  by  affording  easy  access  to  fungi. 

SEASONING. 

The  general  impression  has  been  that  seasoning  wood  makes  it 
more  durable.  In  a  number  of  experiments  made  by  the  Forest 
Service  on  poles  and  ties,  however,  green  wood  has  been  found  as 
durable  as  seasoned  wood.  It  is  questionable,  therefore,  if  it  pays 


FIG.  3. — Fruiting  body  of  fungus,  Polyporus  betulinus. 

to  season  posts  simply  to  increase  their  durability.  If  the  posts  are 
to  be  used  in  moist  locations,  the  seasoned  wood  can  quickly  take  up 
moisture  and  in  a  comparatively  short  time  reach  the  condition  of 
green  wood.  In  any  case,  the  seasoned  posts  will  in  time  reach 
approximately  the  same  condition  as  unseasoned  posts  under  the 
same  conditions. 

In  order  to  be  of  any  value  seasoning  must  be  properly  done,  and 
the  posts  must  not  be  held  so  long  that  decay  begins  before  they  are 


6 


FARMERS     BULLETIN   744. 


set.  The  instructions  for  seasoning  given  on  pages  11  to  12  should 
be  followed.  Posts  should  never  be  left  close  piled  for  any  length 
of  time. 

CHARRING. 

In  some  cases  charring  has  appeared  to  give  good  results;  in  others, 
however,  it  has  failed  to  give  any  appreciable  protection,  and  it  can 
not  be  relied  upon. 

STONES. 

Piling  stones  around  the  base  of  the  post  has  sometimes  been 
resorted  to.  This  tends  to  keep  back  the  weeds  and  allow  the  air  to 


FIG.  4.— Fruiting  body  of  fungus,  Fames  pinicola. 

circulate  freely  around  the  post.  In  some  climates,  however,  where 
the  ground  is  wet  during  a  considerable  portion  of  the  year,  the  use 
of  stones  in  this  way  has  seemed  to  favor  decay  rather  than  retard 
it,  because  the  post  is  allowed  to  dry  out  partially  between  wet 
spells.  It  would  be  better  to  keep  it  constantly  wet. 

In  dry  sandy  regions  posts  are  sometimes  very  badly  cut  by  drift- 
ing sand  being  blown  against  the  wood.  This  effect  is  sometimes 
called  "burning. "  Piling  stones  around  such  posts  would,  no  doubt, 
be  effective  in  preventing  the  sand-cutting.  It  is  doubtful,  however, 
if  results  obtained  by  the  use  of  stones  for  the  sole  purpose  of  pre- 
venting decay  will  justify  the  labor  involved. 


PRESERVATIVE    TREATMENT   OF    FARM    TIMBERS. 


SETTING   IN   CONCRETE. 

Setting  posts  in  concrete  may  have  a  beneficial  effect  in  some  cases. 
If  moisture  should  reach  the  post,  however,  it  may  be  held  there  by 
the  concrete  and 
cause  decay  to 
proceed  more 
rapidly.  This  is 
an  expensive 
method  of  setting 
posts  and  can  not 
be  depended  upon 
to  prevent  decay. 

PROLONGING  THE 
LIFE    OF    POSTS 

BY     MEANS     OF 
PRESERVATIVES. 

REQUIREMENTS   OF 
PRESERVATIVES. 

There  are  five 
chief  require- 
ments  for  a  pre- 
servative for  gen- 
eral use.  It  should 
be  reasonably 
cheap,  should 
penetrate  wood 
readily,  should 
not  be  corrosive 
to  metal,  should 
not  evaporate  or 
wash  out  of  the 
wood  easily,  and 
should  be  poison- 
ous to  fungi.  For 
special  pur- 
poses there  are,  of 
course,  additional 

requirements.  FlG-  5.— Decay  in  top  offence  post  and  adjacent  stringers  due  to  collection 

of  moisture. 

VALUE   OF  VARIOUS  PRESERVATIVES. 

COAL-TAR   CREOSOTE. 

Coal-tar  creosote,  which  is  a  brownish-black  heavy  oil,  practically 
insoluble  in  water,  is  in  general  use  for  preserving  "fence  posts  and 
other  farm  timbers.  Satisfactory  penetrations  of  many  species  of 


8 


FARMERS'  BULLETIN  744. 


wood  can  be  secured  with  it,  and  excellent  results  have  been  obtained 
by  its  use.  It  is  considered  one  of  the  most  efficient  preservatives 
against  decay  so  far  developed  for  farm  timbers  exposed  to  the 


FIG.  6.— Decay  in  braces  at  a  joint  where  moisture  has  collected. 


weather.     It  may  also  be  used  for  inside  work  wherever  its  color, 
odor,  and  other  properties  are  not  objectionable. 

Coal-tar  creosotes  vary  considerably  in  quality;  but  satisfactory 
results  may  be  obtained  from  any  good  grade,  provided  a  sufficient 
amount  is  put  into  the  wood  and  a  good  penetration  is  secured. 
Creosotes  containing  a  high  percentage  of  oils  which  boil  at  a  low 


PEESERVATIVE    TREATMENT   OF    FARM    TIMBERS.  9 

temperature  are  not  so  suitable  for  use  on  the  farm  as  those  which 
contain  a  lower  percentage  of  these  oils,  because  a  considerable  por- 
tion may  evaporate  and  be  lost  during  treatment.  In  some  cases  as 
much  as  one-fifth  of  the  oil  used  has  been  lost  in  this  way.  *  This  loss 
of  oil  by  evaporation  may  be  largely  offset,  however,  by  the  lower 
price  at  which  the  low-boiling  creosotes  may  usually  be  obtained. 
The  increase  in  price  which  can  be  economically  paid  for  the  higher- 
boiling  creosotes  will  in  general  not  be  more  than  from  25  to  35  per 
cent.  Generally,  when  a  considerable  amount  of  creosote  is  to  be 
used,  it  is  purchased  under  specifications.  If  required,  further 
information  on  this  point  can  be  obtained  from  the  Forest  Products 
Laboratory,  Madison,  Wis. 

CARBOLINEUMS. 

Carbolineums  are  proprietary  preservatives  similar  in  appearance 
and  preservative  qualities  to  coal-tar  creosote,  but  usually  higher  in 
price.  In  service  tests  made  by  the  Forest  Service  on  brush-treated 
telephone  poles  they  have  given  about  the  same  increase  in  durability 
as  coal-tar  creosote. 

WOOD-TAR   CREOSOTES. 

But  little  reliable  data  upon  the  effectiveness  of  wood-tar  creosotes 
is  available,  and  until  satisfactory  service  tests  are  completed  no 
definite  recommendation  can  be  made.  It  is  likely,  however,  that 
good  results  will  be  obtained  if  the  wood  creosote  is  of  a  high  grade. 

WATER-GAS-TAR   CREOSOTE. 

Water-gas-tar  creosote  is  an  oil  similar  in  many  ways  to  coal-tar 
creosote,  but  its  value  as  a  fence-post  preservative  has  not  been  fully 
established.  It  is  possible  that  good  results  would  be  obtained  from 
its  use  in  open- tank  work. 

ZINC    CHLORIDE. 

Zinc  chloride  is  a  toxic  preservative  that  gives  good  results  when 
properly  applied  and  used  under  the  right  conditions.  It  is  sold  in 
solid  form  or  in  a  50  per  cent  solution,  and  is  injected  into  the  wood 
in  a  solution  of  from  2  to  5  per  cent  in  water.  It  is  much  cheaper 
than  coal-tar  creosote.  On  account  of  its  solubility  in  water,  how- 
ever, it  is  washed  out  of  wood  in  time  by  the  rain  or  ground  water, 
which  is  the  chief  objection  to  its  use. 

In  general,  zinc  chloride  is  not  considered  as  satisfactory  for  farm 
timbers  as  coal-tar  creosote,  but  there  may  be  cases  where  its  use 
is  advisable.  For  wood  to  be  used  indoors  it  may  in  some  cases  be 
satisfactory  where  creosote  would  be  objectionable  on  account  of  its 
odor,  color,  etc.  It  is  not  recommended,  however,  for  use  by  the 
brush  method. 

41861°— Bull.  744—16 2 


10  FARMEES*   BULLETIN    744. 


Tar  is  not  a  good  preservative  for  farm  use;  and,  in  general,  good 
results  have  not  been  obtained  with  it  when  applied  by  methods  that 
are  practicable  on  the  farm.  Its  chief  defect  is  that  it  does  not 
penetrate  the  wood  readily.  Coal-tar  and  water-gas  tar  are  also  much 
less  poisonous  to  the  organisms  which  cause  decay  than  is  coal-tar 
creosote. 

CRUDE    OIL. 

Crude  oil  is  not  sufficiently  poisonous  for  a  wood  preservative. 
If  the  wood  can  be  thoroughly  saturated  with  it,  water  may  be  kept 
out  and  decay  prevented;  but  it  is  very  difficult,  if  not  impossible, 
to  get  enough  oil  into  most  woods  by  processes  which  are  practicable 
on  the  farm.  For  treating  by  the  brush  method  crude  oil  is  entirely 
unsatisfactory. 

PAINT,  LINSEED    OIL,  WHITEWASH. 

Good  results  can  not,  in  general,  be  expected  from  paint,  linseed 
oil,  or  whitewash  when  used  on  fence  posts  or  other  timbers  in  con- 
tact with  the  ground.  They  do  not  penetrate  the  wood  deeply,  and 
the  only  way  they  can  prevent  decay  is  by  preventing  the  entrance 
of  fungi  or  moisture  into  the  wood.  Furthermore,  the  wood  is 
seldom  painted  on  all  sides;  so  it  is  usually  possible  for  fungus  to 
enter  through  an  unpainted  part.  Whenever,  the  painted  film  cracks 
or  peels  off,  decay  can  also  enter.  It  is  quite  common  to  see  wood 
decaying  beneath  a  coat  of  paint.  (See  figs.  5  and  7).  If  the 
wood  were  saturated  with  linseed  oil  it  might  prevent  decay  by 
keeping  out  the  water;  but  this  would  be  difficult  to  accomplish  as 
well  as  being  too  expensive. 

CEMENT   COATINGS. 

Posts  have  sometimes  been  dipped  in  thin  cement  and  allowed  to 
dry,  leaving  a  coat  of  cement  over  the  surface  of  the  wood.  Such  a 
coating  will  not  keep  out  water  and  is  easily  cracked  or  broken  off. 
Good  results  can  not  be  expected  from  this  treatment. 

PREPARATION   OF   TIMBER   FOR   TREATMENT. 

Only  sound  wood  is  fit  for  treatment.  If  decay  has  made  a  start, 
it  is  not  always  entirely  stopped  by  the  treatment,  but  may  continue 
beneath  the  treated  wood  until  the  interior  of  the  post  is  destroyed. 
The  first  thing  to  consider,  then,  is  the  selection  and  preparation  of 
the  limber. 

PEELING. 

All  timber  should  be  peeled  and  thoroughly  seasoned  before  the 
preservative  is  applied.  In  peeling  posts  of  pine,  cedar,  and  other 
coniferous  woods,  care  should  be  taken  to  remove  the  thin  inner 
bark  from  the  part  of  the  post  that  is  to  be  treated.  Even  small 
patches  of  this  bark  often  prevent  penetration  by  the  preservative. 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS.  11 

(See  'fig.  8.)  When  the  bark  drops  off,  a  patch  of  untreated  or 
poorly  treated  wood  is  exposed,  and  the  opportunity  is  offered  for 
decay  to  enter.  The  effectiveness  of  the  treatment  depends  on 
maintaining  an  unbroken  area  of  treated  wood  entirely  around  the 
post.  In  some  of  the  hardwoods  strips  of  bark  do  not  retard  penetra- 
tion so  seriously. 

BEVELING  TOPS. 

Beveling  the  tops  of  posts  to  a  sharp  edge,  so  that  snow  and  water 
can  readily  drain  off,  is  held  by  some  to  increase  the  durability  of  the 
tops.  Theoretically  this  is  a  good  practice,  but  there  seems  to  be 
little  definite  proof  that  it  results  in  an  appreciable  increase  in  dura- 
bility. 

SEASONING. 

In  order  to  obtain  the  best  absorption  and  penetration  of  preserva- 
tive the  posts  must  be  seasoned.  The  water  and  sap  must  come  out 
of  the  wood  to  make  room  for  the  preservative  to  go  in.  Further- 
more, wood  treated  green  is  likely  to  check  open  after  treatment, 
exposing  untreated  wood.  Seasoned  wood  which  has  been  wet  by 
recent  rains  is  not  in  good  condition  to  treat. 

The  best  place  for  rapid  seasoning  is  an  exposed  location  on  high 
ground.  On  damp  or  low  ground  or  near  a  stream  seasoning  will 
take  place  much  more  slowly,  and  the  wood  will  never  get  quite  so 
dry.  If  properly  piled  in  a  good  location,  posts  will  usually  season 
sufficiently  for  treatment  in  from  60  to  90  days  of  good  seasoning 
weather.  In  exceptional  cases  they  have  been  known  to  season  in  a 
month. 

It  is  sometimes  difficult  to  determine  from  its  appearance  whether 
timber  is  sufficiently  seasoned  or  not.  By  weighing  a  few  representa- 
tive posts  at  regular  intervals  it  is  possible  to  determine  the  degree 
of  seasoning  very  closely.  When  an  ordinary  sized  post  properly 
piled  for  seasoning  does  not  lose  more  than  a  pound  or  two  in  weight 
during  a  week  of  good  seasoning  weather  it  may  be  considered  dry 
enough  to  treat. 


CHECKING. 


Some  woods,  such  as  oak  and  chestnut,  check  very  badly  when 
dried  too  rapidly.  It  is  well,  if  possible,  to  cut  and  peel  such  timber 
in  the  fall  or  winter,  so  that  by  the  time  warm  weather  comes  it  will 
be  partially  seasoned.  Woods  like  pines,  firs,  etc.,  are  usually  not 
affected  so  seriously  as  the  oaks  by  rapid  seasoning. 


PILING. 


The  posts  should  be  open  piled,  so  that  the  air  will  circulate  freely 
around  each  one.  The  bottom  of  the  pile  should  be  raised  6  inches 
or  a  foot  from  the  ground.  Figure  9  illustrates  a  good  method  of 
piling.  Another  method,  but  somewhat  less  desirable  because  one 


12 


FARMERS     BULLETIN"   744. 


end  of  each  post  is  on  the  ground,  is  illustrated  in  figure  10.  If  the 
ground  is  dry,  the  posts  can  be  seasoned  where  they  are  cut  by  laying 
them  upon  rocks  or  brush,  or  keeping  them  off  the  ground  in  any 


FIG.  7.— Painted  post  decayed  at  the  ground  line. 


other  way.  Posts  should  never  be  piled  in  close  piles  or  allowed  to 
lie  on  the  ground;  for  under  such  conditions  they  will  frequently 
start  to  decay  before  they  are  seasoned.  (See  figs.  11  and  12.) 


PRESERVATIVE    TREATMENT   OF    FARM    TIMBERS.  13 

METHODS    OF   APPLYING    PRESERVATIVES. 

There  are  a  number  of  methods  of  applying  preservatives  to  wood, 
and  they  differ  considerably  in  cost  and  effectiveness. 

PRESSURE    PROCESSES. 

Impregnation  under  pressure  is  the  most  satisfactory  means  of 
injecting  preservatives  into  wood.  The  various  pressure  processes 
differ  in  details,  but  the  general  principle  is  the  same  in  all  cases. 
The  wood  is  placed  in  steel  cars  and  run  into  a  long  steel  cylin- 
der. This  is  closed  and  the  preservative  is  pumped  in.  Pressure  is 
then  applied  until  the  desired  quantity  of  preservative  has  been 


FIG.  8.— Treated  pine  tie.    The  light  streak  shows  where  penetration  has  been  retarded 
by  a  strip  of  bark. 

absorbed  by  the  wood.  There  are  over  90  plants  in  the  United  States 
using  pressure  processes,  and  millions  of  gallons  of  coal-tar  creosote, 
zinc  chloride  solution,  and  mixtures  of  the  two  are  used  each  year. 
It  would  be  well  for  anyone  living  within  reach  of  such  a  plant  to 
consider  having  his  timber  treated  there,  if  satisfactory  arrangements 
can  be  made;  for  a-  good  pressure  treatment  will  usually  be  more 
effective  than  any  treatment  that  can  be  made  on  the  farm. 

THE    OPEN-TANK   PROCESS. 

The  open-tank  process  is  the  most  thorough  method  of  treatment 
that  is  practicable  on  the  farm.  The  posts  are  heated  for  one  or 
more  hours  in  the  preservative  (usually  coal-tar  creosote)  at  a  tem- 
perature of  from  180°  to  220°  F.  They  are  then  quickly  transferred 
to  a  tank  of  oil  having  a  temperature  of  about  100°  F.;  and  are  left 


14  FARMERS'  BULLETIN  744. 

there  for  one  hour  or  more.  In  the  hot  bath  the  air  and  moisture  in 
the  wood  expand  and  are  partially  driven  out.  When  the  wood  is 
plunged  into  the  cool  oil  the  air  and  moisture  in  it  contract  and  draw 
the  oil  into  the  wood.  Except  in  the  case  of  a  few  very  easily  treated 
woods,  there  is  little  absorption  of  oil  by  the  wood  during  the  hot 
bath.  Instead  of  a  separate  tank  being  used  for  the  cool  bath,  the 
heating  of  the  oil  in  the  hot  bath  may  be  stopped  and  t*he  wood  and 
the  oil  allowed  to  cool  together.  This  accomplishes  the  same  purpose 
as  the  cool  bath;  but  a  longer  time  is  required  because  the  hot  oil 
cools  very  slowly.  The  single-tank  treatment  is  particularly  suitable 
for  heavy  posts  or  poles  which  can  not  be  easily  transferred  from  one 
tank  to  the  other.  It  can  sometimes  be  used  to  advantage  also  by 
heating  for  two  or  three  hours  early  in  the  morning  or  in  the  evening 
and  allowing  the  posts  to  cool  all  day  or  all  night.  This  will  make  it 


FIG.  9.— A  good  way  to  season  post?. 

possible  to  carry  on  the  treatment  without  interference  with  the 
regular  work  of  the  farm.  The  posts  may  be  treated  more  rapidly, 
however,  by  using  the  two  tanks. 

It  is  desirable  in  the  open-tank  treatment  to  have  the  sapwood 
penetrated  all  the  way  through  by  the  oil.  This  is  sometimes  very 
difficult  to  accomplish,  however,  or  requires  too  much  oil,  and  a 
shallower  penetration  must  then  be  accepted.  A  penetration  of  from 
one-half  to  three-fourths  of  an  inch  should  give  very  good  results. 
Even  lighter  penetrations,  though  they  are  not  recommended,  will 
probably  give  sufficient  protection  to  pay  for  the  cost  of  treating. 
The  treatment  should  extend  far  enough  up  the  post  so  that  at  least 
6  inches  of  treated  wood  will  be  above  the  ground  line  when  the  post 
is  set.  During  the  cooling  period  the  absorption  of  oil  by  the  posts 
will  lower  the  height  of  the  oil  in  the  tank.  Care  should,  therefore, 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS.  15 

be  taken  to  see  that  there  is  always  enough  oil  in  the  tank  to  sub- 
merge the  posts  to  the  proper  depth. 

The  length  of  time  the  wood  is  held  in  the  hot  and  cold  baths 
should  be  determined  by  the  penetration  obtained  and  the  amount 
of  oil  absorbed.  The  best  treatment  is  the  one  that  gives  'the  greatest 
penetration  with  the  least  absorption  of  oil.  The  penetration  may 
be  determined  by  boring  a  small  hole  at  the  point  where  the  ground 
line  will  be.  This  hole  should  be  tightly  plugged  with  a  creosoted 
plug  before  the  post  is  set.  The  reason  for  taking  the  penetration 
at  the  ground  line  is  that  this  is  the  point  at  which  decay  is  usually 


FIG.  10. — Another  method  of  piling  posts  to  season.     Not  so  satisfactory  as  that  shown  in  figure  9. 

most  severe,  and,  therefore,  the  point  at  which  depth  of  treatment  is 
most  important. 

Ordinarily  it  will  not  be  necessary  to  leave  the  posts  in  the  hot 
bath  over  3  hours,  and,  in  many  cases,  a  much  shorter  time  may  give 
good  results.  The  same  is  true  of  the  cold  bath.  If  the  penetration 
of  oil  is  not  sufficient,  either  the  hot  or  the  cold  bath  should  be 
lengthened.  If  the  penetration  is  satisfactory,  but  too  much  oil 
is  absorbed,  the  cold  or  cooling  bath  should  be  shortened.  Green  or 
partly  seasoned  posts  or  posts  wet  from  recent  rains  require  a  much 
longer  hot  bath  than  seasoned  dry  ones.  The  amount  of  oil  absorbed 
per  post  will  vary  with  the  kind  of  wood  and  the  size  of  the  post. 
In  general,  it  should  be  between  four  and  six  tenths  of  a  gallon  for 
a  post  of  from  5  to  6  inches  in  diameter. 

During  the  heating  period  the  temperature  of  the  creosote  should 
be  kept  as  nearly  constant  as  possible;  or,  still  better,  it  should  be 
allowed  to  increase  very  slowly.  It  should  not  be  allowed  to  fluctuate 


16  FARMERS'  BULLETIN  744. 

up  and  down,  if  this  can  be  helped.  Temperatures  between  200° 
and  220°  F.  are  satisfactory.  For  timber  which  treats  very  easily 
180°  may  prove  high  enough.  The  temperature  should  not  be 
allowed  to  go  above  220°,  as  a  certain  amount  of  the  oil  is  lost  by 
evaporation  at  high  temperatures.  There  is  also  danger  that  the 


FIG.  11.— Seasoning  against  a  stump. 

oil  will  boil  over  the  sides  of  the  tank  if  the  temperature  gets  too 
high.  The  "cold"  bath  should  be  warm  enough  to  liquefy  the  oil 
thoroughly.  A  temperature  of  100°  F.  will  usually  be.  found  suffi- 
cient for  this  purpose. 

Various  woods  differ  so  in  their  susceptibility  to  treatment  that 
a  general  rule  for  treating  can  not  be  given.     In  Table  1,  however, 


FIG.  12. — A  close  pile.     A  poor  way  to  pile  posts  for  seasoning. 

are  shown  the  results  obtained  in  some  experiments  with  a  number  of 
kinds  of  wood. 

It  will  be  noted  that  most  of  the  posts  in  Table  1  were  given  a 
light  top  treatment  in  addition  to  the  butt  treatment.  This  is 
necessary  only  when  the  wood  is  of  a  species  that  is  known  to  decay 
rapidly  even  above  the  ground  line,  or  when  the  climate  is  warm  and 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS. 


17 


moist,  as  that  in  some  of  the  southern  States.     The  tops,  however, 
do  not  require  as  heavy  treatment  as  the  butts. 

TABLE  1. — Results  secured  in  the  treatment  of  various  woods. 
[All  posts  were  round,  peeled,  and  seasoned.] 


Species. 

Absorp- 
tion 
per 
5-inch 
post. 

Penetration. 

Single-tank  treatment. 

Double-tank 
treatment. 

2  feet 
from 
butt. 

2  feet 
from 
top. 

Butt. 

Top. 

Hot  oil. 

Cold  oil. 

Hot  oil. 

Cooling 
oil. 

Galls. 
0.4 
.6 
.6 
.6 
4 

In. 
0.4 
.1 
1.0 

.7 
b  .5 

In. 

Hrs. 
5 

Hrs. 
12 

Dippeda 

H.  min. 

H.  min. 

0.05 
.4 
.3 

1 
1 
3 

30 
45 
1 

Beech                              

6 

12 

.6 
.4 
.6 
.6 
.6 
4 

6.3 
b  A 
.6 
.6 
1.0 
.5 

-1 

1    30 

1    30 

6 

12 

.3 
.3 
.3 

1 
1 
1 

1 
1 

45 

6 

12 

Dipped  a 

.6 
.6 
.6 
.5 
.4 
.5 
.6 
.5 
.5 
.5 

.5 

.5 
.6 
.6 
.6 

.4 

1.0 
.2 
&1.0 
b.5 
1.5 
1.2 
1.0 
1.0 
1.0 

.7 

.5 
1.0 

.4 
.6 

.2 
.3 
.1 
.5 
.3 
1.0 
.6 
.3 
.4 
.3 

1 
4 
3 
1 
1 
1    30 
1    30 
3 
3 
3 

2    30 

6 
1 
2 

4 

30 
2 
2 
45 
45 
1 

1 

2 

/     1    30 
\    2 
12 
30 
30 
1 

Oak  pin 

Oak'  red 

Pine'  loblolly 

Pine  pitch 

Pine  shortleaf 

.2 
.2 
.1 
.2 

Tulip  tree 

Willow  white  d 

a  Dipped  for  5  minutes  or  more. 

b  Width  of  sapwood.    Penetration  limited  by  impenetrable  heart. 

c  Average  results  from  6,000  posts. 

d  Requires  especially  thorough  seasoning. 

There  are  two  methods  of  giving  the  top  treatment.  In  one 
method  the  cold  tank  is  made  long  enough  to  hold  the  posts  lying 
full  length.  In  this  case,  when  the  posts  are  transferred  to  the  cold 
tank,  they  are  entirely  submerged  in  the  oil.  This  results  in  a  com- 
paratively heavy  absorption  in  the  butts,  which  have  been  heated, 
but  only  a  light  absorption  in  the  tops.  Another  method  is  to  com- 
plete the  butt  treatment  of  the  posts  first,  and  then  turn  them 
upside  down  in  a  tank  of  hot  oil  and  allow  them  to  remain  for  a  few 
minutes.  The  oil  should  be  deep  enough  in  the  tank  to  cover  all  the 
post  not  treated  before.  If  this  is  not  possible,  a  swab  should  be 
used  to  souse  the  oil  all  over  the  wood  not  submerged.  The  swab 
can  be  made  by  tying  a  piece  of  burlap  on  a  stick.  Particular  pains 
should  be  taken  to  fill  all  checks  and  cracks  with  the  oil. 

Sometimes,  in  seasoning,  the  outer  surface  of  the  wood  becomes 
hard  and  has  a  glazed  appearance.  This  effect  is  called  "case- 


18  FARMERS '   BULLETIN   744. 

hardening/2  and  it  may  seriously  retard  penetration  by  the  oil.  The 
remedy  is  to  shave  off  the  hardened  surface  with  a  draw-shave  for 
from  6  to  8  inches  above  and  below  the  ground  line.  The  rest  of  the 
butt  need  not  be  shaved. 

After  treatment  it  is  a  good  plan  to  stand  the  posts  upside  down. 
This  allows  any  excess  oil  in  the  butts  to  flow  toward  the  top  and 
stay  in  the  wood,  instead  of  dripping  on  the  ground.  They  should 
not  be  left  in  this  position  more  than  a  few  weeks,  especially  if  the 
tops  are  untreated,  as  decay  may  start  in  the  part  which  touches  the 
ground. 

APPARATUS   FOR   OPEN-TANK    PROCESS. 

Various  forms  of  apparatus  are  used  in  open-tank  treatments. 
The  essential  parts  of  the  apparatus  for  general  farm  use  are  one  or 
two  tanks  (depending  on  whether  the  hot  and  cold  or  hot  and 
cooling  method  is  used),  a  thermometer,  and  some  means  of  heating. 

The  chief  requirements  of  the  tanks  are:  (1)  that  they  shall  be 
strong  enough  to  hold  the  weight  of  the  oil  and  the  posts;  (2)  that 
they  shall  not  leak;  (3)  that  they  shall  be  deep  enough  so  that  the 
top  of  the  oil  will  be  a  foot  or  more  below  the  top  of  the  tank  during 
treatment;  and  (4)  that  they  may  be  readily  heated.  Any  tank  of 
convenient  size  which  will  satisfy  these  requirements  will  do.  The 
heating  may  be  accomplished  by  a  fire  beneath  the  tank,  or  by  means 
of  steam  coils,  if  steam  is  available.  If  an  open  fire  is  used,  care 
should  be  taken  to  prevent  the  oil  from  slopping  over  the  side  of  the 
tank  and  taking  fire.  This  is  the  reason  for  having  the  top  of  the  oil 
a  foot  below  the  top  of  the  tank.  Though  the  oil  is  not  dangerously 
inflammable,  and  ordinary  care  will  prevent  trouble,  carelessness  may 
result  in  the  loss  of  the  oil  and  the  posts.  The  treatment  should  be 
made,  of  course,  in  a  situation  where  an  accidental  fire  will  not  en- 
danger any  buildings. 

In  figure  13  is  shown  a  plant  made  from  oil  drums  by  cutting  out 
one  head  of  each  drum.  In  order  to  keep  the  posts  from  floating  in  the 
oil,  it  is  well  in  a  plant  of  this  kind  to  use  a  false  bottom  in  each  drum, 
such  as  is  shown  in  the  figure.  This  can  readily  be  made  out  of  the 
heads  cut  from  the  drums,  or  any  flat  piece  of  iron,  by  riveting  on 
strips  of  iron  through  which  several  screws  protrude  from  one-half  to 
three-fourths  of  an  inch.  The  screws  stick  into  the  posts  and  keep 
them  from  moving  about  and  floating  in  the  oil. 

Figure  14  shows  a  more  permanent  type  of  plant,  in  which  the  tank 
is  made  of  comparatively  heavy  metal  and  is  surrounded  by  a  brick 
fire  box. 

Figure  15  shows  a  plant  built  for  treating  the  entire  post,  giving  a 
heavy  butt  treatment  and  a  light  top  treatment.  The  horizontal 
tank  is  8  feet  long,  3  feet  wide,  and  3  feet  deep ;  the  round  tank,  about 
3  feet  in  diameter  and  4  feet  deep.  The  pole  and  stand  shown  are  for 


PRESERVATIVE    TREATMENT  OF   FARM    TIMBERS. 


19 


use  in  connection  with  the  mortised  board  shown  in  the  rear,  to  hold 
the  posts  under  the  oil  during  the  cold  bath. 

In  figure  1 6  the  details  of  construction  of  the  tanks  used  in  one  ex- 
perimental plant  are  shown.  This  was  a  portable  plant  heated  by 
steam,  which  was  furnished  by  the  boiler  of  a  threshing  engine. 
Between  the  steam  pipes  in  the  bottom  of  the  tanks  strips  of  2-inch 
lumber  studded  with  screws  were  placed  and  firmly  wired  to  the  pipes. 
The  points  of  the  screws  projected  about  three-fourths  of  an  inch 
above  the  wood  and  served  to  keep  the  posts  from  sliding  about. 


FIG.  13.— Treating  plant  made  from  two  oil  drums,  showing  method  oi  constructing  false  bottom. 

Without  the  screws  it  would  have  been  impossible  to  put  a  full  charge 
of  posts  into  the  tank.  On  both  sides  of  each  tank,  about  18  inches 
from  the  top,  2  by  12  inch  planks  were  suspended  by  means  of  l~Lj- 
shaped  irons  which  hooked  over  the  sides  of  the  tanks.  This  made  a 
very  satisfactory  working  platform.  The  capacity  of  the  tanks  was 
from  40  to  105  posts  per  charge,  depending  on  the  size  and  shape  of 
the  posts. 


20 


FARMERS      BULLETIN    744. 


The  number  of  posts  to  be  treated  should  determine  the  character 
of  the  plant  used.  If  only  a  few  posts  are  to  be  treated,  a  simple  plant 
similar  to  that  shown  in  figure  13  is  most  suitable.  For  a  large  num- 
ber of  posts  or  timbers  of  other  kinds,  more  elaborate  apparatus  is 
advisable,  such  as  that  shown  in  figure  16,  or  perhaps  a  stationary 
plant  with  a  complete  equipment  of  a  steam  boiler,  storage  tanks,  oil 
pumps,  a  derrick  for  lifting  the  timber,  etc.  In  any  kind  of  a  plant 


FIG.  14.— Heavy  iron  tank  with  brick  fire  box. 

the  ingenuity  of  the  operator  will  be  called  upon  to  provide  platforms 
and  other  means  of  handling  the  posts  to  the  best  advantage. 

It  may  prove  of  advantage  sometimes  for  a  number  of  farmers  to 
cooperate  in  the  erection  of  a  permanent  plant  of  this  kind  or  a  por- 
table plant,  such  as  that  shown  in  figure  16.  Such  a  plant  could  either 
be  loaned  to  each  of  the  cooperators  in  turn  to  treat  his  own  timber 
or  it  could  be  placed  in  charge  of  an  operating  crew  of  two  or  three 
men  who  would  make  all  the  treatments. 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS. 


COLD-BATH    OR    SOAKING   TREATMENT. 


21 


In  the  cold-bath  process  the  wood  is  treated  by  soaking  for  long 
periods  in  a  tank  of  preservative  at  ordinary  air  temperature.  This 
method  of  treatment  has  not  been  thoroughly  investigated,  but  it  is 
probable  that  but  few  woods  can  be  successfully  impregnated  in  this 
way  with  oils,  since  cold  oils  do  not  penetrate  wood  readily.  Water 
solutions  like  zinc  chloride  would  probably  penetrate  somewhat  more 
readily.  In  any  case  it  would  be  necessary  to  have  the  wood  par- 
ticularly well  seasoned. 


THE    DIPPING    PROCESS. 


The  dipping  process  is  considered  suitable  only  for  preservatives  of 
an  oily  nature.     The  wood  is  simply  heated  in  oil  at  from  200°  to  220° 


FIG.  15. — Experimental  outfit  heated  by  steam.    The  rectangular  horizontal  tank  is  for  the  cold  bath. 

F.  for  from  5  to  15  minutes,  or  longer.  This  allows  all  checks  and 
defects  to  become  filled  with  oil,  but  the  penetration  and  absorption 
of  oil  are  usually  slight.  On  account  of  the  small  amount  of  oil  used 
and  the  large  number  of  posts  that  can  be  treated  in  a  day,  it  is  much 
cheaper  than  open-tank  treatment,  but  it  is  also  much  less  effective. 
Under  no  circumstances  should  any  but  thoroughly  peeled,  well- 
seasoned  timber  be  used.  Unseasoned  wood,  or  that  which  is  wet 
with  snow  or  rain,  is  not  suitable  because  the  oil  will  not  penetrate  it 
readily.  In  very  cold  weather  a  longer  time  in  the  hot  oil  will  be 
required  to  get  the  wood  warm.  The  treatment  should  extend  at 
least  6  inches  above  the  ground  line. 

Dipping  is  more  suitable  for  protecting  the  sapwood  of  compara- 
tively durable  posts  than  for  nondurable  posts.     It  may  add  from 


22 


FARMERS'  BULLETIN  744. 


1  to  3  or  4  years  to  the  life  of  a  durable  post  which  ordinarily  would 
last  8  or  10  years  untreated.  This  is  well  worth  the  cost  of  the  treat- 
ment. An  addition  of  three  or  four  years  to  the  life  of  a  nondurable 


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FIG.  16. — Details  of  construction  of  tanks  for  portable  plant. 

post  which  would  last  only  two  or  three  years  untreated  would  increase 
the  value  of  the  post  more  than  enough  to  pay  for  the  treatment,  but 
it  would  still  have  a  comparatively  .short  life.  If  possible,  non- 


PRESERVATIVE    TREATMENT   OP   FARM    TIMBERS.  23 

durable  species  should  he  given  a  better  treatment,  such  as  the  open- 
tank  or  pressure  treatment. 

The  apparatus  for  dipping  consists  of  a  tank,  a  thermometer,  and 
some  means  of  heating.  Generally,  it  will  he  advisable  to  use  a 
comparatively  small  tank  in  order  that  there  will  not  be  a  large 
amount  of  oil  left  over  after  the  last  posts  have  been  treated. 

BRUSH   TREATMENT   OR   PAINTING. 

Brush  treatment  or  painting  is  also  considered  suitable  for  oils 
only  and  consists  in  applying  two  coats  of  not  preservative  to  the 
wood.  The  oil  should  be  heated  to  from  200°  to  220°  F.  and  flooded 
over  the  wood  rather  than  painted  upon  it.  Especial  care  should  be 
taken  to  fill  every  check  and  defect  in  the  wood,  and  the  first  coat 
should  be  allowed  to  dry  completely  before  the  second  coat  is  applied. 
The  advantage  of  the  painting  method  over  the  others  is  the  small 
amount  of  preservative  it  requires  and  its  cheapness  and  simplicity. 
No  excess  of  preservative  need  be  left  over  after  the  last  post  is 
treated.  It  is  also  of  value  in  treating  portions  of  large  sticks  which 
can  not  readily  be  dipped  or  open-tank  treated,  and  in  treating 
timber  at  joints  and  all  points  of  contact  where  decay  is  liable  to 
occur.  Its  disadvantage  is  that  it  usually  adds  less  to  the  durability 
than  dipping,  open-tank,  or  pressure  treatment. 

Like  dipping,  the  painting  method  is  most  suitable  for  use  on 
peeled,  thoroughly  seasoned,  and  dry  timber.  It  is  best  to  use  it  in 
warm  weather;  for  in  cold  weather,  when  the  hot  creosote  touches  the 
cold  wood,  it  immediately  cools  and  does  not  penetrate  readily. 
Both  treatments  are  more  suitable  for  protecting  the  sapwood  of 
durable  posts  than  for  very  nondurable  posts. 

The  apparatus  for  brush  treatment  consists  of  a  large  kettle  or  pail 
of  some  kind  to  heat  the  oil  in,  a  smaller  pail  to  paint  from,  and  a 
wire-bound,  long-handled  paint  brush.  An  old  broom  might  be 
substituted  for  the  paint  brush  if  desired.  If  a  thermometer  is 
available,  it  can  be  used  to  advantage.  If  none  can  be  had,  the  oil 
should  be  heated  very  hot, but  not  to  boiling.  Care  should  be  exer- 
cised to  prevent  the  oil  from  boiling  over  and  taking  fire. 

Ordinarily  the  oil  is  heated  over  an  open  fire ;  but  in  cases  where  a 
large  amount  of  work  is  to  be  done,  or  the  work  is  widely  distributed, 
it  may  be  found  advantageous  to  use  a  special  oil  heater,  such  as  is 
shown  in  figure  17.  The  heat  is  supplied  by  a  gasoline  blow  torch, 
and  a  thermometer  is  used  to  regulate  the  temperature.  The  pail  is 
made  detachable,  so  that  one  or  more  can  be  in  use  while  another  is 
heating.  The  construction  of  the  heater  is  simple,  and  it  can  be 
made  by  any  competent  tinner. 


24 


FARMERS     BULLETIN   744. 


CARE   OF   TIMBER   AFTER    TREATMENT. 


The  effectiveness  of  any  of  the  methods  of  treatment  which  have 
been  described  is  dependent  upon  keeping  an  unbroken  layer  of  treated 
wood  over  the"  entire  treated  surface. 

Care  should  be  exercised  in  handling  treated  timber  to  see  that  the 
treated  wood  is  not  scraped  away  and  untreated  wood  exposed.  If 
such  an  accident  does  occur  the  exposed  untreated  wood  should  be 
given  two  or  three  coats  of  hot  creosote. 


/7/rtfc/  /no/7  Dad* 


Fro.  17.— Creosote  heater  for  brush  treating. 

Treated  timber  should  never  be  cut  if  it  can  be  avoided.  All  saw- 
ing and  framing  should  be  done,  if  possible,  before  treatment.  If  it 
is  necessary  to  saw  after  treatment,  the  exposed  untreated  wood 
should  be  painted  with  creosote  before  it  is  put  in  place. 

If  butt-treated  posts  or  other  timbers  of  which  only  a  part  is  treated 
are  not  to  be  used  for  some  time,  they  should  be  open  piled  after 
treatment.  If  they  are  close  piled  or  allowed  to  lie  on  the  ground 
for  a  considerable  length  of  time,  decay  is  likely  to  start  in  the 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS.  25 

untreated  parts.     If  the  timber  is  treated  all  over,  it  should  be  close 
piled,  but  the  pile  should  be  raised  off  the  ground. 

In  setting  treated  posts,  poles,  etc.,  great  care  should  be  used  to 
avoid  setting  them  too  deep.  At  least  6  inches  of  treated  wood,  and 
more  if  convenient,  should  extend  above  the  ground  after  the  posts 
are  set.  In  a  number  of  cases  where  this  precaution  has  not  been 
observed  the  posts  have  decayed  above  the  treated  part. 

ADAPTABILITY   TO   TREATMENT. 

As  is  shown  in  Table  1,  some  species  of  wood  are  much  easier  to 
treat  than  others;  and  whenever  there  is  a  choice  between  several 
species  this  fact  should  be  taken  into  consideration. 

In  general,  the  pines  are  very  easy  to  treat.  Other  woods  which 
have  been  found  to  treat  very  readily  in  the  form  of  round  posts  are 
beech,  river  birch,  gum,  pin  oak,  red  oak,  and  sycamore.  Many 
other  species,  however,  can  be  successfully  treated;  and,  in  fact, 
almost  any  kind  of  nondurable  wood  can  be  improved  by  proper 
treatment.  Treatment  will  also  greatly  improve  many  of  the  species 
having  durable  heartwood  and  nondurable  sapwood. 

In  most  woods  the  sapwood  treats  much  more  easily  than  the  heart- 
wood.  In  very  few  species  can  a  satisfactory  penetration  be  ob- 
tained in  the  heartwood  by  the  open-tank  process.  In  general, 
therefore,  a  more  uniform  and  satisfactory  treatment  can  be  ob- 
tained in  round  posts,  of  which  the  entire  outer  surface  is  sapwood, 
than  in  split  or  sawed  posts,  in  which  heartwood  is  necessarily 
exposed.  Among  the  exceptions  to  this  rule  are  hemlock,  in  which 
the  sapwood  is  as  difficult  to  penetrate  as  the  heartwood,  and  syca- 
more, in  which  the  heartwood  is  readily  treated. 

In  some  localities  there  are  considerable  amounts  of  standing  dead 
timber  which  has  been  killed  by  fire,  insects,  or  some  tree  disease,  and 
which  is  still  sound.  For  the  most  part  this  timber  can  be  success- 
fully treated.  Such  timber,  if  it  is  entirely  free  from  decay  and  not 
seriously  injured  by  wood  borers,  is  practically  as  good  as  live  timber 
and  is  well  adapted  to  treatment  because  already  more  or  less  sea- 
soned. It  makes  good  material  for  posts,  poles,  and  many  other  of 
the  common  forms  in  which  wood  is  used.  Blight-killed  chestnut 
and  fire  and  insect  killed  lodgepole  pine  are  in  this  class. 

COST   OF   TREATMENT. 

As  a  rule,  the  principal  item  of  cost  in  the  treatment  of  timber  is  the 
preservative.  The  price  of  creosote  varies.  Near  the  manufac- 
turing plants  it  can  usually  be  obtained  at  from  20  to  35  cents  per 
gallon  in  small  lots.  In  other  localities  the  freight  will  make  the 
price  somewhat  higher.  In  tank-car  lots  the  price  ranges  from  10 
to  25  cents  per  gallon.  It  may  prove  feasible  in  some  cases  for  a 


FARMERS*  .BULLETIN    744. 


number  of  farmers  to  cooperate  in  buying  creosote  in  order  to  obtain 
the  reduction  in  price  due  to  purchasing  in  larger  quantities.  The 
exact  cost  in  any  case  will  have  to  be  determined  by  inquiring  of  the 
dealer  from  whom  the  oil  is  to  be  obtained. 

The  cost  of  applying  the  preservative  depends  mainly  upon  the 
number  of  posts  to  be  treated,  the  cost  of  apparatus,  labor,  and  fuel, 
and  the  number  of  posts  which  can  be  treated  per  day.  The  number 
of  posts  treated  per  day  will,  of  course,  vary  according  to  their  size 
and  ease  of  treatment,  the  size  of  the  plant,  etc.  Fuel  and  labor 
charges  are  sometimes  ignored  in  fence-post  treatment,  and  the 
number  of  posts  treated  per  day  is  then  not  quite  so  important. 
The  cost  of  treatment  will  vary  greatly  in  different  localities,  and  in 
accordance  with  differing  local  conditions,  so  that  a  general  cost- 
figure  can  not  be  given.  In  Table  2,  however,  are  given  some  figures 
obtained  in  the  open-tank  treatment  of  posts  in  several  localities. 
The  cost  of  oil  may  now  be  somewhat  greater  than  that  given  in  the 
table.  The  cost  of  the  apparatus  is  not  included  in  the  calculations. 

TABLE  2. — Cost  of  treatment  under  certain  conditions. 


Locality. 

Kind  of  post. 

Cost  of  oil. 

Cost  of 
treat- 
ing. 

Total 
cost  of 
treat- 
ing. 

Remarks. 

Per 
gallon. 

Per 
post. 

Louisiana 

Loblolly  pine  
Scrub  pine  

SO.  15 

.15 
.12 

.12 
.24 

$0.09 

.09 
.06 

.06 
.12 

$0.01 

.01 
.01 

.01 
.07 

$0.10 

.10 

.07 

.07 
.19 

Entire  post  impregnated,  cost 
of  labor  not  included. 
Do. 
Butt  impregnated,  topdipped, 
cost  of  labor  not  included. 
Do. 
Butt    impregnated;     cost    of 
labor  included  at  $2.50  per 
day. 

Maryland  

Maine 

Quaking  aspen  
Cottonwood  

Minnesota. 

California 

Western  yellow 
pine. 

VALUE    OF   TREATMENT. 


Unless  a^  reasonable  saving  can  be  effected  by  preservative  treat- 
ment of  wood,  the  expense  involved  is  not  justified.  The  saving 
due  to  preservative  treatment  will  depend  upon  local  conditions.  In 
some  localities  durable  posts  are  expensive  and  difficult  to  obtain; 
while  nondurable,  easily  treated  woods  are  abundant  and  cheap.  It 
is  in  such  localities  that  treatment  is  particularly  desirable.  In 
other  localities  there  may  be  a  plentiful  supply  of  durable  timber 
which  can  be  obtained  very  cheaply.  In  such  places  it  may  not  be 
advisable  to  attempt  preservative  treatment. 

The  chief  points  which  must  be  considered  in  determining  whether 
treatment  will  pay  are  the  comparative  cost  and  average  life  of 
untreated  and  treated  posts.  The  cost  and  approximate  life  of  un- 
treated posts  of  the  different  species  in  common  use  in  any  locality 
will  generally  be  known  to  the  residents  of  that  locality.  It  is  esti- 


PRESERVATIVE    TREATMENT   OF   FARM    TIMBERS.  27 

mated  that  a  thorough  open-tank  treatment  of  fence  posts,  for  ex- 
ample, a  heavy  butt  treatment  and  a  light  top  treatment,  will  give 
even  to  nondurable  woods  an  average  life  of  at  least  20  years.  This 
estimate  is  based  on  the  best  information  obtainable  on  the  dura- 
bility of  creosoted  posts  and  other  creosoted  timber.  It  can  not  be 
considered  as  conclusive,  however. 

In  estimating  the  cost  of  an  open-tank  treated  post  the  chief  items 
to  be  considered  are  the  original  cost  of  the  post  and  the  cost  of  the 

011  absorbed.     In  general,  from  four-tenths  to  six-tenths  of  a  gallon  of 
creosote  will  be  required  per  post.     The  cost  of  labor  may  or  may 
not  be   included,   according   to   the   individual   circumstances.     In 
order  to  get  a  close  estimate  of  the  annual  charge,  the  cost  of  setting 
the  post  and  interest  on  the  investment  are  sometimes  included  in 
the  calculations. 

If  it  is  found  in  a  certain  locality  that  cedar  posts  which  will  last 

12  years  can  be  obtained  for  30  cents  and  that  treated*  pine  which 
will  last  20  years  can  be  obtained  for  the  same  price,  money  will  be 
saved  by  using  the  treated  pine ;  or,  if  a  locust  post  can  be  obtained 
for  35  cents  and  a  treated  beech  post  which  will  probably  last  about 
as  long  costs  half  as  much,  it  will  be  economical  to  treat  the  beech. 
On  the  other  hand,  if  an  untreated  post  which  will  last  12  years  can 
be  obtained  for  10  cents  and  a  treated  post  which  may  be  expected 
to  last  20  years  costs  30  cents,  it  will  not  be  economy  to  treat. 


SERVICE  TESTS  OF  TREATED  POSTS. 


To  obtain  more  exact  information  about  the  average  life  of  treated 
posts  under  various  conditions,  experimental  posts  are  being  tested 
in  fences  in  many  parts  of  the  country  and  careful  records  of  their 
durability  are  being  kept.  In  Table  3  are  given  the  results  so  far 
obtained  in  a  number  of  these  experiments. 


28 


FARMERS     BULLETIN    744. 


Remarks. 

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PRESERVATIVE    TREATMENT  OF   FARM    TIMBERS.  29 

PROLONGING  THE   LIFE   OF   OTHER  FORMS   OF  FARM   TIMBERS. 

There  are  many  forms  of  timber  used  on  the  farm  to  which  treat- 
ment can  be  advantageously  applied.  Among  these  are  silos,  rural 
telephone  poles,  shingles,  greenhouse  boards,  sills,  foundation  tim- 
bers, bridge  timbers,  board  walks,  wooden  gates,  windmill  frames, 
porch  columns,  well  curbing,  etc.  The  treatment  of  any  nondurable 
wood  which  is  used  where  conditions  are  favorable  to  decay  is  worthy 
of  careful  consideration. 

SILOS. 

A  thorough  treatment  with  coal-tar  creosote  will  make  a  wooden 
silo  more  resistant  to  decay  and  less  subject  to  shrinking  and  swelling. 
It  will  also  make  painting  unnecessary. 

The  most  satisfactory  way  to  inject  creosote  into  silo  staves  is  by 
impregnation  under  pressure.  It  may  sometimes  be  possible  for  a 
farmer  to  haul  his  untreated  silo  to  a  creosoting  plant  and  have  it 
treated,  but  pressure  treatments  will  usually  have  to  be  made  by  the 
manufacturer  before  the  silo  is  sold.  Some  manufacturers  are  already 
doing  this,  and  it  is  now  possible  to  purchase  a  pressure-treated  silo 
all  ready  to  set  up. 

Next  to  pressure  treatment,  open-tank  treatment  is  best;  but  on 
account  of  the  length  of  the  staves  and  the  long,  narrow  tank  re- 
quired it  may  be  inconvenient  to  use  this  method.  A  good  combi- 
nation treatment  would  be  to  give  the  lower  2  or  3  feet  of  each  stave 
an  open-tank  treatment  and  the  remainder  a  two-ooat  brush  treat- 
ment. If  this  is  done,  the  part  of  thai  staves  most  subject  to  decay 
will  receive  the  heaviest  treatment.  All  the  wood  which  touches  the 
foundation  should  be  thoroughly  treated.  As  with  any  treated  tim- 
ber, no  sawing  or  cutting  that  can  be  prevented  should  be  done  after 
the  wood  is  treated.  All  untreated  surfaces  necessarily  exposed  by 
cutting  should  be  heavily  painted  with  the  preservative. 

Brush  and  dipping  treatments  are  less  efficient  than  open-tank 
or  pressure  treatments  and  will  not  give  as  great  an  increase  in  dura- 
bility. They  may  be  used  to  advantage,  however,  when  the  better 
methods  are  entirely  out  of  the  question. 

One  possible  objection  to  the  use  of  creosoted  lumber  in  silos  is 
that  the  silage  might  be  contaminated  by  creosote  bleeding  from  the 
wood.  Information  obtained  by  the  Forest  Service,  however,  indi- 
cates that  there  is  little  danger  of  this  if  proper  care  is  used.  In 
order  to  prevent  contamination,  the  treated  wood  should  be  thor- 
oughly air  seasoned  in  open  piles  after  it  is  treated  and  before  it 
is  put  into  the  silo.  In  the  case  of  open-tank  or  pressure  treatments, 
the  absorption  of  oil  should  not  exceed  8  or  10  pounds  per  cubic 
foot. 


30  FARMERS '   BULLETIN    744. 

Of  the  woods  in  general  use  for  silo  construction,  the  pines  are, 
as  a  class,  the  most  easily  treated;  hemlock,  tamarack,  spruce,  and 
Douglas  fir  are  somewhat  more  difficult.  With  pressure  treatment 
the  greatest  saving  can  usually  be  effected  by  using  the  cheaper 
woods,  as  the  difference  in  the  durability  of  the  various  species  is 
less  after  treatment  than  before.  It  is  questionable  if  the  treatment 
of  such  durable  species  as  heart  redwood  and  heart  cypress  would  pay. 

SHINGLES. 

The  application  of  paint  is  the  preservative  measure  most  com- 
monly used  for  shingles;  and,  if  the  paint  is  properly  applied,  it 
will  add  to  their  durability  by  protecting  them  from  the  weather, 
keeping  out  moisture,  and  preventing  cupping.  If  it  is  not  properly 
applied,  however,  it  may  even  hasten  decay.  From  a  preservative 
standpoint,  the  best  way  to  apply  the  paint  is  by  dipping  the  shingles 
in  it.  This  may  be  found  impracticable,  however,  since  the  amount 
of  paint  which  would  adhere  to  the  shingles  would  in  many  cases  be 
too  great  unless  some  means  were  provided  to  brush  off  the  excess. 

When  the  shingles  are  painted  after  the  roof  is  laid,  a  ridge  of 
paint  is  liable  to  form  at  the  base  of  each  shingle.  This  tends  to 
hold  the  water  after  a  rain  and  keep  the  shingles  moist,  thus  making 
conditions  more  favorable  to  decay. 

Brush  treatment  with  creosote  or  a  good  shingle  stain  does  not 
leave  a  ridge  like  ordinary  paint  and  can  be  recommended  as  good 
practice,  but  dipping  the  shingles  in  the  preservative  is  better  in  this 
case  also.  The  best  results  in  preventing  decay  are  obtained,  how- 
ever, by  first  heating  and  then  cooling  the  wood  in  the  preservative, 
as  described  for  the  treatment  of  fence  posts. 

The  open-tank  process  has  already  been  explained.  The  apparatus 
used  for  posts  may  be  employed;  or  if  shingles  exclusively  are  to  be 
treated,  the  form  of  the  outfit  may  be  modified.  The  simplest  appa- 
ratus is  a  single  tank  large  enough  to  hold  a  bundle  of  shingles.  If  a 
larger  capacity  is  desired,  the  depth  rather  than  the  width  should  be 
increased;  for,  in  order  to  minimize  the  loss  of  oil  by  evaporation, 
the  oil  surface  exposed  to  the  air  should  be  kept  as  small  as  possible. 
The  best  treatment  for  various  kinds  of  shingles  has  not  yet  been 
determined.  The  most  desirable  treatment  is  the  one  which  gives 
the  best  penetration  with  the  least  absorption  of  oil.  Sap-pine 
shingles,  thoroughly  seasoned,  can  be  completely  penetrated  without 
difficulty,  but  cedar  shingles  are  more  difficult  to  treat.  The  proper 
treatment  in  any  case  must  be  determined  by  observing  the  absorp- 
tion of  oil  and  the  penetration  secured  and  varying  the  treatment 
accordingly.  The  oil  should  not  be  allowed  to  get  too  hot,  however, 
or  the  shingles  held  in  it  for  too  long  a  time;  for  in  either  of  these 
events  the  shingles  may  become  somewhat  brittle. 


PRESERVATIVE    TREATMENT   OF    FARM    TIMBERS.  31 

While  creosote  treatment  can  be  expected  to  increase  very  mate- 
rially the  resistance  of  shingles  to  decay,  the  treated  shingles  possess 
certain  objectionable  qualities  which  should  be  kept  in  mind  when 
considering  their  use;  for  instance,  their  strong  odor  and  their  con- 
tamination of  cistern  water.  Further,  since  the  shingle  nails  become 
covered  with  creosote  and  can  not  be  held  in  the  workman's  mouth, 
it  is  said  to  be  more  difficult  to  lay  these  shingles.  The  odor,  how- 
ever, disappears  in  the  course  of  a  few  weeks — 2  weeks  in  one  case 
observed.  The  contamination  of  the  cistern  water  may  be  of  longer 
duration,  though  in  one  instance  the  water  was  tasteless  after  3  days 
of  rain.  All  these  objections  may  be  lessened  if  the  shingles  are  sea- 
soned for  a  few  weeks  between  treating  and  laying. 

It  is  held  by  some  that  creosote  treatment  makes  shingles  more 
inflammable  and  thus  increases  the  fire  danger,  and  it  seems  probable 
that  this  is  true  to  a  cerain  extent.  It  is  a  point,  however,  which  has 
never  been  satisfactorily  settled. 


TELEPHONE   POLES. 


When  farmers'  cooperative  telephone  lines  are  constructed,  the 
treatment  of  the  poles  will  frequently  effect  a  saving  in  the  cost  of 
upkeep.  The  open-tank  treatment  will,  of  course,  give  a  much  longer 
life  than  brush  treatment;  but  the  cost  of  the  tanks,  the  extra  oil 
required,  apparatus  for  handling  the  poles,  and  the  extra  labor  may 
not  be  justified  unless  a  large  number  are  to  be  treated.  Brush  treat- 
ment will,  therefore,  in  many  cases  be  the  most  practicable  method 
to  use.  For  the  reasons. given  in  the  discussion  of  the  dipping  and 
brush  treatment  of  posts,  however,  brush  treatment  of  poles  is  most 
suitable  for  treating  the  sapwood  of  durable  species.  Poles  of  non- 
durable species  should,  if  at  all  possible,  be  given  a  better  treatment, 
such  as  open-tank,  or  even  pressure  treatment.  In  most  parts  of 
the  United  States  a  butt  treatment  is  sufficient  to  protect  the  poles; 
but  in  the  warm,  moist  climate  of  the  southern  States  it  is  necessary 
to  treat  the  entire  pole,  especially  if  sap  pine  or  other  nondurable 
woods  are  used. 

The  tops  of  the  poles  and  the  gams  cut  in  the  poles  to  hold  the 
cross-arms  should  be  brush  treated.  Pole  braces  should  be  treated 
like  the  poles.  Wherever  a  pole  brace  touches  a  pole,  both  should 
be  brush  treated  at  the  point  of  contact. 


BRIDGE   TIMBERS. 


Treatment  of  the  timbers  and  planks  of  permanent  bridges  will 
add  materially  to  their  resistance  to  decay.  Open  tank  and  pressure 
treatments  are  the  best.  Brush  or  dipping  treatments  of  the  face  of 
the  planks  would  soon  be  worn  away  and  would  be  of  little  value; 
but  they  may  be  used  to  advantage  in  other  parts  of  the  structure. 


32 


FARMERS     BULLETIN   744. 


SILLS   AND    FOUNDATION    TIMBERS. 

Sills  and  foundation  timbers  in  contact  with  the  ground  or  with 
stone  or  concrete  foundations  frequently  decay  rapidly,  and  pre- 
servative treatment  is  advisable.  It  is  probable  that  brush  treat- 
ment will  usually  be  found  the  only  convenient  way  to  treat  such 
timbers  on  account  of  their  size,  but  wherever  possible  better  treat- 
ments should  be  used. 

LUMBER   USED  IN   GREENHOUSES. 

Lumber  used  in  greenhouses  is  usually  subject  to  rapid  decay, 
which  can  be  greatly  retarded  by  preservative  treatment.  If  creo- 
soted  boards  are  used  close  to  steam  pipes,  however,  some  of  the  oil 
is  volatilized  by  the  heat,  and  the  fumes  have  a  bad  effect  on  the 
plants.  In  other  parts  of  the  greenhouse,  where  the  boards  are  not 
exposed  to  heat,  the  creosote  has  been  found  to  have  no  bad  effect 
on  the  plants.  It  is  desirable  in  all  cases  to  air  season  the  boards 
thoroughly  after  treatment  before  putting  them  in  service,  in  order 
to  prevent  the  possibility  of  creosote  bleeding  from  them  after  they 
are  installed.  Creosotes  containing  comparatively  large  amounts  of 
low-boiling  oils  are  not  as  suitable  for  greenhouse  timbers  as  the  oils 
of  higher  specific  gravity,  because  they  are  much  more  volatile. 

JOINTS   AND   POINTS   OF   CONTACT. 

Experience  has  shown  that  in  any  timber  structure  where  th^ 
wood  comes  in  contact  with  wood,  stone,  or  other  material  decay  is 
liable  to  occur  more  rapidly  at  the  point  of  contact  than  in  other  parts 
of  the  structure.  If  it  is  impracticable  to  treat  the  timber  for  the 
whole  structure,  it  will  frequently  be  profitable  to  give  a  good  brush 
treatment  to  the  joints  and  other  points  where  decay  is  usually  most 

severe. 

CONCLUSION. 

In  every  locality  the  question  of  preservative  treatment  of  fanr 
timbers  should  be  given  careful  consideration.  It  is  often  difficult 
for  a  farmer  to  treat  his  own  material  efficiently.  This,  however 
does  not  indicate  that  the  work  should  be  neglected,  but  only  tha 
some  other  means  of  securing  the  desired  result  should  be  sought 
There  are  two  practical  methods  of  doing  this.  One  is  for  som- 
individual  to  undertake  the  work  for  the  neighborhood.  In  man^ 
cases  a  small  wood-preserving  plant  could  be  profitably  operated  ii 
connection  with  a  threshing  outfit,  a  feed  mill,  or  sawmill.  Th 
other  plan  is  for  several  individuals  to  cooperate  in  establishing  an« 
operating  a  plant.  The  means  may  vary,  but  it  can  not  be  to 
strongly  emphasized  that  every  agricultural  district  should  po 
the  facilities  for  increasing  the  durability  of  farm  timbers  by 
servative  treatment. 

WASHINGTON  :    GOVERNMENT  PRINTING  O' 


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